The singer or the woman in this song learned her mistakes and she won't let her heart broken again by her ex-bf whom she loved very much.
This song really relates to me - how he wanted me back after hurting me so much and how I said 'no'.
And the song obviously states she loves this person so much because if not she will not be hurt this much.
She waited for the love promised to her.
Atleast now i'll know how to spot a guy with a jar of hearts.
This song can look like it is between to lovers.